View Javadoc
1   /*
2    * Copyright 2012 The Netty Project
3    *
4    * The Netty Project licenses this file to you under the Apache License,
5    * version 2.0 (the "License"); you may not use this file except in compliance
6    * with the License. You may obtain a copy of the License at:
7    *
8    *   http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13   * License for the specific language governing permissions and limitations
14   * under the License.
15   */
16  package org.jboss.netty.handler.codec.serialization;
17  
18  import java.io.EOFException;
19  import java.io.IOException;
20  import java.io.InputStream;
21  import java.io.ObjectInputStream;
22  import java.io.ObjectStreamClass;
23  import java.io.StreamCorruptedException;
24  
25  class CompactObjectInputStream extends ObjectInputStream {
26  
27      private final ClassResolver classResolver;
28  
29      CompactObjectInputStream(InputStream in, ClassResolver classResolver) throws IOException {
30          super(in);
31          if (classResolver == null) {
32              throw new NullPointerException("classResolver");
33          }
34          this.classResolver = classResolver;
35      }
36  
37      @Override
38      protected void readStreamHeader() throws IOException {
39          int version = readByte() & 0xFF;
40          if (version != STREAM_VERSION) {
41              throw new StreamCorruptedException(
42                      "Unsupported version: " + version);
43          }
44      }
45  
46      @Override
47      protected ObjectStreamClass readClassDescriptor()
48              throws IOException, ClassNotFoundException {
49          int type = read();
50          if (type < 0) {
51              throw new EOFException();
52          }
53          switch (type) {
54          case CompactObjectOutputStream.TYPE_FAT_DESCRIPTOR:
55              return super.readClassDescriptor();
56          case CompactObjectOutputStream.TYPE_THIN_DESCRIPTOR:
57              String className = readUTF();
58              Class<?> clazz = classResolver.resolve(className);
59              ObjectStreamClass streamClass = ObjectStreamClass.lookup(clazz);
60              if (streamClass == null) {
61                  // If streamClass is null its very likely that we had an old netty version that was writing an
62                  // interface with a thin descriptor. Fall back to use ObjectStreamClazz.lookupAny(..) to resolve
63                  // it.
64                  //
65                  // This will only work on java6+ but if we hit this line its very likely that a user is upgrading
66                  // from netty 3.2.x which was using the method before and so use java6+.
67                  //
68                  // See https://github.com/netty/netty/commit/6c2eba79d70a532822a0e38092faa9783d90906b
69                  streamClass = ObjectStreamClass.lookupAny(clazz);
70              }
71              return streamClass;
72          default:
73              throw new StreamCorruptedException(
74                      "Unexpected class descriptor type: " + type);
75          }
76      }
77  
78      @Override
79      protected Class<?> resolveClass(ObjectStreamClass desc) throws IOException, ClassNotFoundException {
80          Class<?> clazz;
81          try {
82              clazz = classResolver.resolve(desc.getName());
83          } catch (ClassNotFoundException ex) {
84              clazz = super.resolveClass(desc);
85          }
86  
87          return clazz;
88      }
89  
90  }